This is a divisional of Ser. No. 743,585 filed as PCT US84/01354 filed Aug. 24, 1984, published as WO85/00963, Mar. 14, 1985, .sctn.102(e) date Oct. 7, 1984.
To those familiar with instant adhesives, it's no surprise that their vapors can expose fingerprints with the white residue caused by monomer "blooming". In fact, efforts to reduce this undesirable behavior date from the early days of cyanoacrylate technology.
However, it was left until much later to discover that this same process could be turned to the noble task of apprehending criminals through fingerprint identification. In 1978 the Tokyo Metropolitan Police are reported to have hosted a demonstration of cyanoacrylate fuming for development of fingerprints by criminologists of the Japanese National Police Agency. In May of 1979, Detective Inspector N. Edmunds and L. Wood of Northamptonshire (England) Police are reported to have observed that fingerprints were developed when they repaired a black plastic developing tank with Loctite Super Glue.TM.. Within a month, they reported their findings to a regional police conference.
Constable Paul Bourdon of the North Bay Ontario Police Force was an early practitioner of the method and invented a fuming system which generates vapor in one chamber and pumps it into another which contains the evidence under investigation. His system has been patented in the U.S. and Canada (U.S. Pat. No. 4,297,383, incorporated herein by reference).
Frank Kendall of the U.S. Bureau of Alcohol, Tobacco and Firearms, developed an improvement in the method which uses cotton treated sodium hydroxide to accelerate the generation of vapors. A description of this technique is given in Identification News, June 1982, page 3.
The use of heat to accelerate generation of cyanoacrylate vapors for fingerprint development use has also been reported. Identification News, January 1983, page 9, and May 1983, page 10.
The cyanoacrylate vapor technique has become an accepted method for fingerprint development. In several cases, identifications have been made on evidence for which no previous methods had been workable. Recently, evidence provided by this method has been accepted in a Kansas court leading to criminal conviction. Abele, Identification News, February 1983, page 12.
Recognized benefits of using cyanoacrylate monomers to develop fingerprints which have been discovered to date are as follows:
(a) Development of latent prints on objects where other methods have failed; PA0 (b) development of prints on difficult surfaces such as polyethylene bags or electrical tapes; PA0 (c) print images produced are easier to handle than powder-dusted prints which may blow away; PA0 (d) large enclosed areas, such as automobile interiors can be fumed for prints. PA0 1. Sodium hydroxide is a poison and corrosive, and can cause damage to skin if not mixed wearing gloves. PA0 2. Preparation time is substantial. PA0 3. The technique provides a small amount of fumes for the amount of adhesive used. Most of the adhesive polymerizes, within the saturated pad or as visible white smoke, rather than being evaporated into the atmosphere within the chamber. The polymerized white smoke does not react with the latent print. PA0 4. Fumes from the pads rise to the top of the chamber, then filter down, failing to provide uniform exposure of the objects being processed to the vapors. PA0 1. Temperature setting can be critical. Too hot may result in overdevelopment of the print and failure of the adhesive to polymerize within the print. Too cool may result in failure of the adhesive to be absorbed into the chamber as quickly as desired, requiring longer processing. PA0 2. Use in smaller chambers, even in small amounts, may result in overdevelopment if the items being processed are not closely monitored. PA0 3. Various methods of using heat as an accelerant also heat the entire chamber, affecting vinyls and plastics (especially black vinyl tapes). PA0 4. Minor accidents involving the use of heated objects may result in burns or damage to the chamber. PA0 1. No poisons or corrosives. PA0 2. No preparation time. PA0 3. Produces an even amount of exposure to the adhesive evaporated within the chamber over a 20-minute plus time period. PA0 4. Provides evaporation from a larger surface area than previous methods. PA0 5. Room temperature operation. No critical effects of minor variations in the temperature. PA0 6. No heat to destroy vinyls or plastics. PA0 7. Overdevelopment does not occur in a short period of time. Items can be left in the chamber up to one hour over the amount of time required without loss of ridge detail (items, as in previous methods, should not be placed closer than 3 inches to the envelope). PA0 8. No burns or damaged chambers. PA0 9. No spillage of adhesive or contamination of evidence. PA0 10. Substantially reduces complexity of cyanoacrylate use making it feasible for use in the field by minimally trained technicians.
The significant benefits of the cyanoacrylate fingerprint development technique, however, have been accompanied by other notable disadvantages. These disadvantages include the instant bonding of cyanoacrylate adhesives to skin and clothing when contacted by evidence technicians. Also, the typical low viscosity cyanoacrylate adhesive used in the prior techniques is easily spilled or dripped. This not only contributes to inadvertent bonding of clothes and skin but can also result in damage to the evidence. Initially, without acceleration of vapor generation, it has been reported that full development of a print takes at least about five hours and can take as long as 90 days.
With acceleration of vapor generation, other disadvantages have been identified as follows:
Disadvantages of Sodium Hydroxide Acceleration:
Disadvantages of Heat Acceleration: